Thank you, TC. The Best Kept Secret obviously does not apply to those of you trained and flying in the UK. But here across the pond we apparently have a different situation. The Best Kept Secret is not that cyclic must be applied quickly to stop and reverse falling rotor rpm. The "secret" is what will happen if the rotor rpm falls below the critical point for the particular make and model and the flight variables that exist at the time power to the rotor fails. Most helicopter pilots, from new to old timers, don't realize or believe that when this happens, there is absolutely no recovery from the situation, and that pilot and passengers are just along for the ride.
I have great admiration for the test pilots who gather the data needed to pinpoint the lower red line on the rotor tach of each make and model, and this lower red line must work for all possible combinations of load, DA, airspeed, c.g., etc., and must have some sort of cushion, too. I respect and teach pilots to observe these limits, and I have no desire to explore them with the engine(s) flamed out.
Almost every poster assumes the pilot will have both hands on the controls at all time. This is simply not true! As I pointed out in an earlier post, the collective is nothing more than a thrust control. All of us at times are not guarding the collective, and if a problem happens the cyclic should be brought aft without hesitation while moving one's left hand back to the collective.
Note that I say "Cyclic back and collective (lever) down simultaneously, or in that order." It is simply wrong in my opinion to prioritize the collective ahead of the cyclic, especially if one's left hand is not on the collective. This would mean not moving the cyclic until the left hand could find the collective and lower it. This would be a huge mistake.
And some posters say that the amount of aft cyclic should be determined by such things as airframe attitude, load, speed, DA, c.g., etc. Why? Why not treat cyclic back the same as lever down? When the engine fails do you stop and think about how far down you should lower the lever? Of course not. You lower it rapidly and fully, and then, if you determine that some pitch is needed for some reason, you raise the lever accordingly.
The same should be true for the cyclic...and even more so. There is no harm at all in starting the cyclic back immediately to stop, not slow, the reduction of rotor rpm, which is all that lowering the lever does.
The first group that needs to know about the Best Kept Secret is the old timers who have never heard of it. This obviously excludes those of you fortunate enough to be trained in the UK. The second group is the flight instructors who have never heard about it, and we've got plenty of them in the business (again, not in the UK). And the third group consists of the FAA and NTSB and the people who write and/or control the publications we depend on such as the PTS, the rotorcraft flight manuals and the slew of FAA-approved helicopter-related publications that do not even mention applying aft cyclic for any reason at all.
Pete Gillies